Revision as of 16:52, 22 March 2013

Using Gnuk on Debian Wheezy

This is a quick tutorial on how to get your public and private key to work with the Flying Stone Tiny[1] GPG token. All the information here was taken from the complete documentation of Gnuk written by its author[2]. Benefits of the Flying Stone Tiny-01 include: a) keeping your secrets separated from a hard-disk, which is a common medium for the storage of GPG secrets and could potentially represent a major security risk; b) ability to use your keys in multiple computers; c) hardware-lock preventing the secrets to be read from the token; d) it is USB, which means it is (almost) universal, dipensing the need for a Smart Card reader, while having all the benefits of a smart card; d) it is all free software-based (GPLv3), therefore it is not only transparent and widely available, but also free for further improvements and new inventive usages.

After completing the tutorial, if you still have questions, access the Q&A forum [3] and check Riseup's tutorial [].

1. Check requerements for using the GPG token:

- Your GPG keys must be RSA 2048 bits, if your keys do not met the requirement, generate new keys[4];
- FST-01 USB token with Gnuk pre-installed (click here for alternatives);
- GNU/Linux system (should work on other *nix systems, but not yet tested).

4. In order to use the token, make sure you are running gpg-agent, if not:

Run gpg-agent:

gpg-agent --daemon --enable-ssh-support

5. If you are planning to use the token to authenticate with OpenSSH

Generate your ssh keys [5]:

gpgkey2ssh ADD_YOUR_SUBKEY_ID_HERE >> sshpubkey.txt

Add your pub key to the server you want to auth with your GPG token:

ssh ~/.ssh/authorized_keys

6. Personalize your token

To change your personal info, URL where your pub key is, etc., run:

gpg --card-edit
gpg> admin
Allow admin commands to be executed
gpg> name
Register name and surname of the token owner
gpg> url
Address for the location of your public keys, important setting to help you register the token in other machines
gpg> passwd
Set-up your PIN for the usage of the token, please this is not your 'passphrase' for the GPG private key
The default PIN from the factory is "123456"; your new PIN should not be bigger than 8 characters.
It does not have to be numbers -- the acronym PIN is misleading here.
gpg> forcesig
This will change the default setting of 'signature force PIN' OFF
gpg> login
Register your login name
gpg> help
This is command is your friend, if you want to further customize the token!
gpg> save
This will apply the changes

gpg --edit-key ADD_YOUR_KEY_ID_HERE
gpg> keytocard
This command will *move* your pub GPG key to the token
gpg> toggle
This command changes from pub key to the private key operation
gpg> keytocard
This command will move your private key to the token
gpg> save
This command will save the info to the token and exit the shell

8. Using your keys in other computers with GPG installed

Invoke the GPG shell with this command:

gpg --card-edit
gpg> fetch
This command will retrieve your keys and add it to the local GPG keychain

The key is now registered by your local install of GPG, but you have to set the trust of it:

gpg --edit-key ADD_YOUR_KEY_ID_HERE
gpg> trust
This command will set the key you just installed as 'trusted'. Given it is your own key, set it to (5) 'ultimate' trust

9. Before you use the token, make sure you deactivate other gpg agents. Here are some popular agents:

- gnome-keyring (GNOME)
- kwallet (KDE)
- seahorse

10. Access '/etc/xdg/autostart' and '~/.config/autostart' and add a new entry to the following config files:

Add this line to 'gnome-keyring-ssh.desktop':

X-GNOME-Autostart-enabled=false

Add this line to 'gnome-keyring-gpg.desktop':

X-GNOME-Autostart-enabled=false

11. Common Issues

* If you get the 'OpenPGP card not available: general error', try killing gpg-agents, such as gnome-keyring;
* If you type a wrong PIN three times, you will lock the device permanently, *be extra carefull*!
* If you need to re-write keys to the token, make sure to delete the keys on it first [6].